I have read each of them and have begun looking at the online textbook provided by Shirley for reference. Apologies for not following proper protocol with putting the full verse in the original post.

Back to the subject matter, when I took a class on the book of Revelation in college by a professor that of course spoke and read Greek, he taught on Revelation 1:1 that the verse gives a succession of the revelation, being handed down from God->Jesus->Angel->John->Bond-Servants.

NIV Translation: The revelation from Jesus Christ, which God gave him to show his servants what must soon take place. He made it known by sending his angel to his servant John,

So it seems that you are all in agreement that adverbial participle ἐσήμανεν ἀποστείλας has the subject of Θεός,. So in the NIV translation "He made it known by sending his angel" the He and his refer to God Θεός, and not Jesus Christ Ἰησοῦ Χριστοῦ,. So according to the text, there are really two separate successions: God->Jesus and then God->Angel->John->Bond Servants according to this verse.

Not that I do not trust your take on this verse, but what exactly is it that shows that that ἐσήμανεν ἀποστείλας is talking about God and not Jesus. Is it simply that Θεός has the nominative form marking the subject while Ἰησοῦ and Χριστοῦ, have the genitive form showing possession, or are there additional clues that point towards this.

Thanks again.

The participle is in the nominative case, and has to refer to the subject, which is God, also in the nominative. It's not a matter of trust, but a matter of fact, which will resolve as you study the language.